silverstorm

I know I'll catch flak for trying to get one of these to work since all you rich people have gone to the native support MS's but I really enjoy using my self-soldered DIYPNP since I'm trying to do every part of this build first hand that I can.

That being said, I can connect to the box with the VVTuner software but get 0 RPM signal.
- DIYPNP running off CAS so only VVTuner is getting crank/cam signals. Car runs great without VVT but want all the twerks.
- Already checked crank wheel
- Confirmed 12V, ground, and signal from sensors (ckp and cps are powered and signal forwarded through now unused egr plugs, grounded directly to engine)
- I know VVTuner has control of OCV since you can hear the valve click if you plug it in with car off, and with car on it runs like on 2 cylinders at idle and dies
- VVTuner reads MAP as accurately as Tuner Studio

Re-reading DIY's instructions I thought maybe I needed to do this:
"If the VVTuner CCM and EMS share the same ground or a direct ground to the EMS is undesirable, pins 9 and 10 can be connected together either by way of a short piece of wire or a solder bridge between the two pins."

Below picture shows ugly solder blob connecting 9 and 10.


This led to blowing the fuse the VVTuner is running off of. It's powered via the power antenna plug in the trunk which is on a 15A fuse with the stereo. Before the solder it didn't blow the fuse.

So, what am I doing wrong besides refusing to spend $1000 on an MS that will make this easy mode? Could my sensors be bad? Is there a way to test? Thanks for any help!

-Billy

MX5RACER

Have you checked the sensor air gap for the crank sensor? I have been using a VVTuner in both my racecar and street Miata for a few years now as I started with a DIYPNP and it was cheaper to just add the VVTuner.

I run the sensor wiring through the factory CAS wiring on my racecar ('90) and inside the DIYPNP, I go from the sensor outputs on the break out board to the expansion connector along with 12+ and ground to the VVTuner. I then run the VVTuner as a pass-thru back to the DIYPNP through the same plug (Different pins of course) and to the DIYPNP mainboard to the sensor inputs.

Good luck.

gooflophaze

My guess is you put the solder blob on 14 and 15, not 9 and 10, since you flipped it over. Looks like 14 and 15 are ground and the solenoid output.

silverstorm

I'll double check the crank gap. I hope it's good as is because the bolt hole that holds the sensor felt like it started stripping out the last time I tightened it. Thank you for the recommendation though.

gooflophaze, that would definitely explain blowing a fuse. I had confirmed with a multimeter that I was soldering the right pins but it makes too much sense not to confirm again.

gooflophaze

On the DB15 face there should be the pin numbers embossed by the pins - might have to catch the light just right to see them. It's always annoying to try and infer them from documentation because it'll be reversed male to female / documented from the front and back.